2024/05/08 by Chen, Zhaoting, Pourtsidou, Alkistis
#Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2405.05414
We study the viability of using power spectrum clustering wedges as summary statistics of 21cm surveys during the Epoch of Reionization (EoR). For observations in a wide redshift range z∼ 7-9 corresponding to a line-of-sight scale of ∼ 500Mpc, the power spectrum is subject to anisotropic effects due to the evolution along the light-of-sight. Information on the physics of reionization can be extracted from the anisotropy using the power spectrum multipoles. Signals of the power spectrum monopole are highly correlated at scales smaller than the typical ionization bubble, which can be disentangled by including higher-order multipoles. By simulating observations of the low frequency part of the Square Kilometre Array (SKA) Observatory, we find that the sampling of the cylindrical wavenumber k-space is highly non-uniform due to the baseline distribution, i.e. the distribution of antenna pairs sampling different transverse k_⊥ scales. Measurements in clustering wedges partition the cylindrical k-space into different radial k_∥ scales, and can be used for isolating parts of k-space with relatively uniform sampling, allowing for more precise parameter inference. Using Fisher Matrix forecasts, we find that the reionization model can be inferred with per-cent level precision with ∼ 120hrs of integration time using SKA-Low. Compared to model inference using only the power spectrum monopole above the foreground wedge, model inference using multipole power spectra in clustering wedges yields a factor of ∼ 3 improvement on the marginalised 1D parameter constraints.